Bit holder for cutter chain bits



5, 1959 c. H. BROWN 2,901,233

BIT HOLDER FOR CUTTER CHAIN BITS Filed Nov. 18, 1957 Fig. 4' I2 IN VENTOR.

' ij 2 Clarence H Brown M 1 "T a.

A TTORNEV nited St tes en 2,901,233 Patented Aug. 25, 1959 ManufacturingCompany, Chicago, 111., a corporation of Illinois Application Novemberis, 1957, Serial No. 696,982 1 Claim. 01. 262-33) This invention relatesto improvements to cutter chain blocks particularly adapted forcontinuous mining machines and the like, and more particularly relatesto a simplified and improved detachable mounting for the cutter chainbit in its chain block.

A principal object of the present invention is to provide a simplifiedholding means-for a cutter chain bit in its chain block which eliminatesthe use of the usual set screws for holding the bit to its block.

Another object of the invention isto provide a new and improved cutterchain'block having a simplified holdin-g means for holding the cutterchain bit to the block so arranged as to tighten the bit within theblock by the cutter forces acting on the bit and to accommodate readyrelease of the bit from its block.

Another object of the invention is to provide a selfretaining holdingconnection for a cutter chain bit to its block in which the cuttingforces acting on the bit and block serve to tighten the bit to its blockand in which the bit may readily be removed from its block by a simpleprying action on the holding means therefor.

A still further object of the invention is to provide a self-retainingholding device for holding a cutter bit to its block, in which a strapextends from the block and has an inner face conforming to a face of thecutter bit, and in which a bit holder is slidably movable within saidstrap and has faces facing the inner face of said strap, for engagementwith opposite cutting faces of the bit, and forcing the bit intoengagement with the inner face of: said strap by the cutting forcesacting on said bit.

These and other objects of the invention will appear from time to timeas the following specification proceeds and with reference to theaccompanying drawings wherein:

Figure 1 is a view in side elevation of a cutter chain block and bit,with the bit holding portion of the block broken away and shown insection in order to show the bit holder structure of the invention;

Figure 2 is a front end view of the cutter chain bit and block shown inFigure 1; and

Figure 3 is a fragmentary sectional view taken substantially along line3-3 of Figure 1.

In the embodiment of the invention illustrated in the drawing, referencecharacter designates generally a cutter bit carrying cutter chain block.The cutter chain block 10 is one of a plurality of links of a cutterchain used for cutting coal in mines underground and guided for orbitaltravel in the usual guide or cutter bar indicated by dot and dash linesin Figure 2 and designated by reference character 11.

The cutter chain block 10 is shown as including a lug 12 having spacedlink portions 13 formed integrally therewith and extending from oppositesides thereof and having gibs 14 extending along the inner sidesthereof, for engagement with the conventional guides in the cutter bar.

The link portions 13 are shown as being drilled at 15 to accommodate theblocks 10 to be connected together in the form of a continuous chain bythe usual connecting straps or links (not shown) pivotally connectedthereto by pivot pins (not shown), as is Well known to those skilled inthe art, so not herein shown or described further. i

The-Iug 12 is herein shown as having parallel spaced sidewalls 16,spaced inwardly from the outer faces of the link portions 13. The sidewalls 16 are engaged by the inner faces of parallel spaced legs 17 of abit retaining strap 19, secured to said lug as by roll pins 20 or a likesecuring means, which may readily be removed by a punch or the like, toaccommodate the removal of said strap from said lugs. d

The bit retaining strap 19 has generally a V-shaped closed end portionhaving inner faces 21 terminating at an apex 23. The faces 21 and apex23 are inclined outW-ardlyfrorn the rear to the forward end of saidstrap at the angle of an outer edge 24 of a cutter bit 25 to reactagainst and pitch said cutter bit at the required cutting angle.

The cutter bit 25 is of a well known form of cutter bit, commonly knownas a throw-away type of cutter bit, diamond shaped in cross-section.Said cutter bit has oppositely inclined faces 26 inclined inwardly frompositionsadjacent the transverse center of the bit, from the oppositeedge of the bitfrom the edge 24, and forming cutting points at thejunctures of said inclined faces with thecdge 24, and thus providing areversible bit of an economical construction, which may be thrown awaywhen worn. The bit 25 is retained in position within the strap 19 by abit holder jaw 27 slidably mounted on the outer face of the lug 12within the legs 17 of the strap 19, for slidable movement along said lugand strap.

The bit holder 27 has outer faces 29 and 30 conforming to the angle ofinclination of the inclined faces 26 of the bit 25 and connectedtogether by a rectilinear face 31 inclined at the angle of the edge 24of the bit. The face 21 with the oppositely inclined faces 29 and 30forms a recess for receiving the bit 25 and retaining said bit to thestrap 19, by the cutting forces acting on said bit and said bit holder.

As herein shown, the lug 12 has spaced cars 33 and 35 extendingoutwardly therefrom, forming slidable mountings for a pin 36 extendingthrough spaced ears 37 and 39, extending inwardly from the bit holder27.

The bit holder 27 is shown as being retained to the pin 36, as by a pin40 or like retaining device, and is shown as being biased toward therear of the lug 12 as by a compression spring 41, encircling the pin 36and interposed between the ear 33 extending from the lug 12 and the car39 extending from the bit holder 27.

The spring 41 thus biases the bit holder inwardly along the strap 19 andaccommodates said bit holder to be moved outwardly of said strap in aforward direction by a pry bar 42. The pry bar 42 has a C-shapedengaging end portion engageable with a recess 43 in the outer face ofthe strap 19, and with the rear face of the bit holder 27, to force saidbit holder in a forward direction with respect to the strap 19 upon theexertion of a prying force on the bar 42 in a direction, which is shownin Figure l as being in a clockwise direction.

Thus, when it is desired to insert a bit within the bit holder it ismerely necessary to force the bit holder 27 outwardly with respect tothe strap 19 and tothen insert a bit therein into engagement with theinclined faces 29 and 3t) and then release the holder and accommodatethe spring 41 to bias the bit holder into engagement with the bit and tobias the bit into engagement with the inclined faces 21 of the strap 19.

It may be seen from the foregoing that a simplified form of bit holderparticularly adapted for bits of the throw-away type has been provided,which does away with the usual set screws and like securing devices and.

makes it possible to replace the bit by a simple prying action on therear face of the bit holder.

It may further be seen that the cutting forces on the bit and bit holderforce the bit into engagement with the inclined faces 21 of the strap19, to retain said bit to said strap by the normal cutting forces actingthereon, and that the harder the cutting forces, the greater will be theretaining pressure of the bit to the strap and lug.

While I have herein shown and described one form in which my inventionmay be embodied, it should be understood that various modifications andvariations of the invention may be effected without departing from thespirit and scope of the novel concepts thereof as defined by the claimappended hereto.

I claim as, my invention: 5

In a cutter block, a cutter bit adapted to be held in place in saidblock, said bit being generally diamond shaped in cross-section andhaving oppositely inclined faces inclined from one edge portion of thebit from positions adjacent the transverse center of the bit to oppositeends of an opposite edge portion of the bit and defining cutting pointsat opposite ends of said opposite edge portion of the bit, said cutterblock having a lug extending longitudinally therealong having parallelspaced longitudinally extending side walls and an outer face inclinedoutwardly from the rear to the forward end of said lug havinglongitudinally spaced ears extending outwardly therefrom, means forsecuring said bit to said lug comprising a strap generally U-shaped incross-section having a closed outer end portion and parallel legsextending therefrom along opposite sides of said lug, means detachablysecuring said parallel legs to said lug, the inner wall of the closedouter end portion of said strap having inner bit engaging surfacesinclined outwardly from an apex to conform to the sides of saidbit andinclined outwardly from the rear to the forward end of said strap at thecutting angle of said bit, a bit holding jaw slidably guided on theouter inclined face of said lug between the legs of said strap andhaving oppositely inclined advance and retreating bit engaging facesfacing the closed end of said strap and conforming to the oppositelyinclined faces of said bit for retaining said bit into engagement'withthe apex of the inner wall of said strap by the action of the cuttingforces on said bit, said jaw having longitudinally spaced ears extendinginwardly therefrom in 'ad- References Cited in the file of this patent AUNITED STATES PATENTS 2,020,215 Ross Nov. 5, 1935 2,156,726 Fulke May 2,1939 2,263,590 Osgood Nov. 25, 1941 2,389,936 Rupp Nov. 27, 19452,404,540 Simmons July 23, 1 946

